Grinding machine and method



Feb. 18, 1958 R. M. ARBUQKLE 2,823,492

GRINDING MACHINE ma METHOD 9 Sheets-Sheet 1 Filed July l6, 1954 ATTORNEYFeb- 18, R558 R. M. ARBUCKLE ETAL 2,82

GRINDING MACHINE AND METHOD Filed July 16, 1954 e Sheets-Sheet 2INVENTORS ATTORNEY BY JBJep/Z/X 7/07/2501 Feb. 18, 1958 R. M. ARBUCKLEEI'AL 2,823,492

GRINDING'MAQHI NE AND METHOD 9 Sheets-Sheet 5 Filed July 16, 1954INVENTORS ATTORNEY Feb. 18, 1958 R. M. ARBUCKLE ETAL I 2,823,492

GRINDING MACHINE AND METHOD l 9 Sheets-Sheet 5 Filed July 16, 1954INVENTORS TTOR HEY Feb. 18, 1958 R. M. ARBUCKLE ETAL GRINDING MACHINEAND METHOD 9 Sheets-Sheet 6 Filed July 16, 1954 INVENTORS 1958 R. M.ARBUCKLE ETAL 2,823,492

GRINDING MACHINE AND METHOD 9 Shegts-Sheet 7 Filed July 16, 1954 fi Fm Jm Feb. 18, 1958 9 Sheets-Sheet 8 Filed July 16, 1954 QE M Feb. 18, 1958R. M. ARBUCKLE ETAL 2,823,492

GRINDING MACHINE AND METHOD 9 Sheets-Sheet 9 Filed July 16, 1954INVENTORS ATTORNEY GRINDING MACHINE AND METHOD Robert M. Arbuckle,Shelbyville, and Joseph R. Hamilton,

Indianapolis, Ind., assignors to General Motors Corporation, Detroit,Mich., a corporation of Delaware Application July 16, 1954, Serial No.443,854

7 Claims. (Cl. 5132) This invention relates to contour or profilegrinding nited States Patent 0,

machines and more particularly to machines for grinding I forged orrough cast turbine bucket blades to within prescribed tolerances.

In high speed turbines it is necessary that each blade of the turbinewheel be precisely the same or closely identical to every other blade ofsuch wheel. The high speeds at which turbine wheels are rotatedaccentuates every blade defect and magnifies the resultant unbalanceforce. In order to prevent the destruction of the turbine wheel andirreparable damage to the turbine and surrounding equipment it hasheretofore been necessary that each turbine blade be individuallymachined to within very close tolerance dimensions to assure theiridentity within prescribed limits. The machining of each bladeindividually is costly in time and labor.

It is now proposed to provide a means of grinding a rough cast or forgedturbine bucket blade to within the prescribed tolerances. Heretoforesuch grinding of a turbine blade has been considered impractical becauseof the wearing away of the grinding wheel and a consequent difliculty inmaintaining the prescribed tolerances. The grinding machine proposed isprovided with means for obviating this objection by compensating forgrinding wheel wear. It is proposed to rotate each turbine blade, inrough form, about an axis parallel to that of the grinding wheel and tomove the grinding wheel along the length of the blade as the blade ismoved transversely with respect thereto and in conformance with thedictates of a master cam. Inasmuch as the workpiece or blade is movedrelative to the grinding wheel and engages the grinding wheel atprogressive positions along its peripheral edge it is proposed that aworn grinding wheel may be adapted for such movement as will enableengagement with the workpiece at such progressive positions. Suchmovement of a worn grinding wheel may be accomplished by mounting thegrinding wheel drive motor upon a cradle having a fixed axis of rotationand by eccentrically positioning the axis of the worn grinding wheelfrom the cradle axis so that rotation of the cradle will cause the worngrinding wheel to describe an arcuate path which will dispose the wornwheel at the progressive positions along the arcuate path which theworkpiece is adapted to travel.

It is therefore an object of the proposed invention to provide a machineand method for grinding turbine bucket blades and to provide means forcompensating for grinding wheel wear. It is an object of this inventionto provide a master cam adapted to control the contour grinding of arough cast or forged turbine blade and to provide a corrector cam tocompensate for grinding wheel wear. It is further an object of thisinvention to provide a fully automatic profile grinding machine foraccurately and rapidly grinding a turbine blade to prescribetolererances and readily adaptable for repeated operation in grindingnumerous blades without renewing the grinding wheel used therewith. Theproposed machine is adapted to perform the required grinding operationin a minimum 2,823,492 Patented Feb. 18, 1958 of time with small cost inlabor and materials. The use of forged or cast blades in the proposedmachine greatly minimizes the machining time heretofore required. Theuse of a grinding wheel and its adaptability for continued use despitewear is of great savings in tooling heretofore necessary. The overallcost of producing turbine blades is therefore greatly reduced without asacrifice of quality and with considerable savings in time, labor, andmaterials.

Although the principles of this invention are here related to a grindingmachine they may obviously similarly be adapted for use in a millingoperation wherein a milling cutter wheel rather than a grinding wheel isemployed.

Figure l is a side view of the proposed profile grinding machine havingparts broken away and shown in cross section.

Figure 2 is a top view of the proposed grinding machine taken in theplane of line 2-2 of Figure 1 and looking in the direction of the arrowsthereon.

Figure 3 is an enlarged top view of one end of the proposed grindingmachine including the work holder and having parts broken away and shownin cross section.

Figure 4 is an enlarged top view of the other end of the proposedmachine including the grinding means and having certain parts brokenaway and shown in cross section.

Figure 5 is an enlarged end view of the proposed grinding machineshowing the means for compensating for grinding wheel wear. Figure 5 istaken in the plan of line 55 of Figure 1 looking in the direction of thearrows thereon.

Figure 6 is an enlarged cross-sectional view of the other end of thegrinding machine taken in the plane of line 6-6 of Figure 2 and viewedin the direction of the arrows thereon.

Figure 7 is an enlarged cross-sectional view taken through the workholder in the plane of line 7.7 of Figure 2 and viewed in the directionof the arrows thereon.

Figure 8 is a view of a part of the grinding machine showing the endmounting of the corrector cam as viewed in the plane of line 8-8 ofFigure 5 in the direction of the arrows thereon.

Figure 9 is an enlarged cross-sectional view of a part of the proposedgrinding machine taken in the plane of line 9--9 of Figure 2 and viewedin the direction of the arrows thereon.

Figure 10 is a diagrammatic illustration of the fluid lines employedwith the proposed grinding machine.

Figures 11, 12 and 13 are diagrammatic illustrations of the relationbetween the workpiece and grinding wheel during progressive stages ofthe grinding operation.

The proposed turbine bucket or blade contour grinding machine includes abase member 10 having a work device 12 mounted upon a table 14 slidableupon one end of the base member and work holder 16 mounted upon theother end of the base member and adapted for transverse movement withrespect to the table. A workpiece 18 is supported within the work holder16 and is adapted for rotation and translation relative to thelongitudinal movement of a rotating grinding wheel 20 of the work device12. A master cam 22 mounted in the work holder 16 controls the gyrationof the workpiece 18 about the grinding wheel 20 and a correction cam 24associated with the work device 12 controls the gyration of the grindingwheel relative to the workpiece as necessary to compensate for grindingwheel wear.

Referring to Figure 5, the table 14 is adapted for longitudinal guidedmovement along the top of the base member 10 by means of a guide rail 26formed on the base member and received within a groove 28 formed in theunderside of the table. Depending side rails 30 of the table 14 overlaythe sides of the base 10 and are formed 3. inwardly to engage grooves 32provided in the sides of the base member. Movement of the table 14 iseffective by a hydraulic cylinder 34 secured to the base member andconnected by the piston rod 36 to a depending flange 38 of the table.

Trunnion supports 40 and 42 are secured to the table 14 and are spacedapart to support a cradle 44 therebetween. A grinding wheel drive motor46 is mounted upon the cradle 44. The forward upright 48 of the cradle44 and the forward support 40 have enlarged openings 50 and 52 formedtherein through which the shaft or drive spindle 54 of the grindingwheel motor 46 is extended; the forward end of the cradle being pivotalupon a pivot bearing ring 56 extended between the support 40 and cradleupright 48. The rearward cradle upright 58 has a pivot shaft 59 securedthereto and journaled within the after support 42.

The grinding wheel drive motor 46 is supported on the cradle 44 on apair of slide blocks 60 and 62 which enable axial and lateral adjustmentof the drive motor relative to the pivotal axis of the cradle member.The drive motor 46 is secured to slide block 60 which is itselfadjustable within guideways '71 formed from slide block 62. This slideblock 60 is adjustable lengthwise of the cradle by adjustment of thegraduated knob 73 connected to shaft 74 having worm 76 on the endthereof and which engages the worm wheel 78 to rotate shaft 80 threadedthrough a nut member 84 fixed to the underside of the slide 60 (seeFigures 1 and 9). The slide block 62 is adjustable transversely of thecradle, within guideways 63 thereof, by means of a graduated knob 64connected to a shaft 66 which is engaged with the slide and is threadedas at 68 through an upright support 69 secured to the side of thecradle.

Set screws 70 are provided to fix the motor 46, and its longitudinallyadjustable slide block 60, in an adjusted position relative to slideblock 62. Slide block 62 remains laterally adjustable by threaded shaft66 (with either shaft 80 having a U-joint therein or nut 84 beingpivotally connected to the underside of slide 60).

These adjustments of the grinding wheel motor 46 are provided for thepurposes of setting the position of the grinding wheel 20 relative tothe workpiece 18 for the work stroke required and for moving the axis ofrotation of the grinding wheel from a position coincident with thecradle axis with an unworn grinding wheel to a position off center fromthe cradle axis commensurate with grinding wheel wear, as will bedescribed.

The grinding wheel 20 is secured to the shaft 54 of the drive motor 46beyond the trunnion support 40. A grinding wheel dresser 86 is mountedupon the table 14 and is pivotally supported upon a mounting stand 88for move ment into or out of engagement with the face of the grindingwheel 20. The wheel dresser 86 is shown in dressing position in Figures1 and 2 and as pivoted out of the way in Figure 4. The grinding wheel 20is moved relative to the dressing member 90 by transverse movement ofthe grinding wheel motor 46 on slide block 60.

A cradle stop 92 is secured to the table 14 beneath the cradle 44 andcomprises a cam 94 adapted to be rotated for engagement or disengagementwith a depending lug 96 on the cradle. The engagement of the cam 94 withthe lug 96 raises the cradle 44 in a position which prevents rocking thecradle within the supports 40 and 42 as will later be described. Whenthe flat side of the cam 94 is up the cradle 44 is free to rotate.

The work holder 16 includes a housing 98 having a driven shaft 100journaled therein with a worm wheel 102 secured to one end and themaster contour cam 22 secured to the other end. A work spindle 104 isjournaled within the work holder housing 98 and is aligned with thedriven shaft 100 and secured thereto through a spline connection withcam 22, which is itself connected to a flange of shaft 100. A work chuck106 with locking jaws 108 is secured to the outer end of the spindle 104and is adapted to receive the workpiece 18 and to hold the workpiece inoutwardly extended relation towards the grinding wheel 20.

The work holder housing 98 is mounted upon a supporting platform 110secured to the base member 10 and within a ball-track 112 formedtransversely across the platform as shown by Figure 1. Referring toFigure 7, a hydraulic power cylinder 114 secured to the platform 110 isconnected by a piston rod 116 to a depending portion 118 of the housing98 and is adapted to urge the housing and more particularly the mastercam 22 against a cam follower 120 secured to the table 14. The camfollower 120 includes an upstanding support 122 secured to the table andadapted to dispose the follower adjacent the master cam 22. As the table14 is moved longitudinally the housing 98 is adapted to movetransversely with respect thereto against the bias of the hydrauliccylinder 114. The hydraulic cylinder 114 is further adapted to move themaster cam 22 out of engagement with the cam follower 120 by means ofthe piston rod 116 acting against the depending portion 118 of thehousing to the limits of the stop-plate 124 secured to the housing 98and adapted to engage the platform 110.

Referring to Figures 3 and 6, the Worm wheel 102, within the work holderhousing 98, is driven by a worm 126 secured to a shaft 128 journaled inthe base of the housing. The end of the shaft 128 is pinned as at 130 toa splined female connector 132 which receives the splined end 134 of anintermediate shaft 136 journaled within the platform support 110,thereby allowing relative movement of the work holder housing 98 axiallyof the intermediate shaft. The intermediate shaft 136 is pinned to aconnector 138 keyed as at 140 to the drive shaft 142 of a hydraulicmotor or other drive source 144.

A worm 146 keyed as at 148 to the intermediate shaft 136 meshes with aworm wheel 150 mounted upon a second drive shaft 152 extendedlongitudinally along the outside of the base 10. Referring to Figure 4,the drive shaft 152 includes two parts 154 and 156 joined by a connector158 and journaled within the platform support 110 and two bearingsupports 160 and 162 secured to the base member 10. As shown by Figures4 and 8, the correction cam 24 is secured to the drive shaft 152intermediate the two bearing supports 160 and 162. A cover plate 164 issecured to the one support 162 over the end of the drive shaft 152.

A cam follower 166 is adapted to engage the correction cam 24 and ismounted on an extended arm 168 keyed as at 170 to a stub shaft 172journaled within the rack andv pinion housing 174; which housing isintegrally a part of the after trunnion support 42 secured to themovable table 14. A rack sector 176 is also secured to the stub shaft172 and is disposed in meshing engagement with a pinion 178 secured tothe cradle pivot shaft 59. A coil spring 180 is secured to the after endof the pivot shaft 59 between the shaft and the cover plate 182 securedto the housing 174 thereover. The spring 180 is adapted to balance theweight of the cradle 44 and thereby assist the rack 176 in moving thecradle.

The cam follower 166 moves with the table 14 longitudinally along thebase 10 and thereby is moved along the corrector cam 24. The follower166 is adapted to normally engage the cam 24 at its smallest radius. Thefollower 166 is held in engagement with cam surfaces of larger radius bythe gravitational weight of the cradle 44 which at such larger radiiacts to bias the follower against the corrector cam 24.

The operation of the grinding machine is hydraulically controlled. InFig. 10 there is shown a fluid tank 184 and pump motor 186 which may bedisposed apart from the grinding machine but which are connected theretoby fiuid lines as hereinafter described. The main drive motor 144 of thecontour grinding machine is connected by lines 188 and 190 to the fluidtank 184. In the present instance a constant displacement piston typefluid motor is used. A cam operated metering or flow control valve 192is connected between the flow lines 188 and 190 to regulate the speed ofthe drive motor 144 by control of the fluid flow. A pilot valve 194 isconnected by line 196 to a control valve 187 in line 188 for startingthe fluid drive motor 144.

Fluid from the tank 184 is conveyed through line 198 to the controlvalve 200 which when actuated allows fluid to pass through lines 202 and204 to control valve 206 and to the flow metering valve 208respectively. Fluid passing through the control valve 206 is normallyadapted to flow through line 210 past the pressure reducing valve 212,check valve 214 and relief valve 216 to one side of the hydrauliccylinder 114 for controlling movement of the work holder housing 98 inone direction. Such direction is normally to bias the master cam 22against the cam follower 120. The fluid passing through the meteringvalve 208 reaches control valve 218 through line 220 where it is appliedvia line 222 to one side of the hydraulic cylinder 34 connected to thebase and adapted to move the table 14 in one direction by means ofpiston rod 36 connected to the depending flange 38 thereon.

The table 14 advances at a rate set by the metering valve 208. The workholder housing 98 is moved transversely thereto by the cam follower 120engaged against the master cam 22 until the bracket 223 of table 14, asshown by Figure 1, contacts limit switch 224. The actuation of limitswitch 224 stops the travel of table 14 and diverts the fluid flowthrough control valve 206 from line 210 to line 226 where it isintroduced to the other side of the hydraulic cylinder 114. Referring toFigure 7, the work holder housing 98 is moved in a direction to disposethe master cam 22 beyond the reach of the cam follower 120. The Workholder housing 98 engages limit switch 228 at the end of its travelwhich switch diverts the fluid flow through control valve 218 from line222 to line 230 and causes a rapid return of the table 14 to itsoriginal position. The table 14 contacts limit switch 232 which isadapted to shut off the grinding wheel drive motor 46.

A control panel 242 is secured to the machine in any convenient locationas to the support 110 and includes three separate control buttons 244,246 and 248 connected to various units of the proposed machine in aconventional and well known manner. The button 244 actuates the controlvalves 206 and 218 to start the advance of the work holder and table,the button 246 starts the grinder motor 46' and the button 248 is forthe immediate return of the Work holder 96 and table 14 to theiroriginal positions. In an emergency the work holder housing 98 isbacked-off and the slide table 14 returned, with a consequent shuttingoff of the grinding wheel drive motor 46, by the actuation of button 248diverting the flow of fluid away from hydraulic cylinder 114, throughrelief line 234, and directly back to the fluid tank 184. The fluid isat the same time diverted through line 226 to the other side of thehydraulic cylinder 114 causing the work holder housing 98 to back ofi,actuating limit switch 228, diverting fluid flow in cylinder 34, andreturning the table 14 to its original position.

A general diagrammatic representation of the relation of the workpiece18 and grinding wheel 20 is given in Figures 11, 12 and 13. Thesefigures show a new grinding wheel 235, a worn wheel 236, and theirrespective drive spindles 238 and 240 respectively. The workpiece 18, orturbine blade as here shown, is illustrated against a rectangularbackground 241, representative of the blade holding means, to moreclearly designate the change in position through the three stages given.The relation of the blade to the representative holding means isunchanging.

Taking into consideration first a new grindingwhee l 235 which is notworn, it will be seen that the rocking of the cradle 44 caused by theengagement of the cam follower 166 with the correction cam. 24, throughthe rack and pinion 176 and 178, will not affect the grinding wheelsince its axis of rotation is coaxial with the pivotal axis of thecradle. The workpiece 18 is rotated and moved relative to the grindingwheel 20 in conformance with the dictates of the master cam 22 as thetable 14 moves the grinding wheel 235 along the length of the workpiece.The workpiece 18 rotates about its own axis and is moved transversely tothe grinding wheel 235 as prescribed by the master cam 22 and engagesthe grinding wheel 235 so far as is necessary to perform the requiredtolerance grinding. The master cam 22 controls the grinding of bothsides of the workpiece 18 as the grinding wheel 235 moves inwardlytherealong.

After the grinding wheel 235 becomes worn to the size of wheel 236 it isapparent that the wheel being smaller in diameter cannot grind to therequired tolerance. lt'is therefore necessary that the wheel 236 bedisposed in such a manner that its grinding surface will follow theperipheral path of the original wheel 235. This is accomplished bymoving the slide block 60 upon which the grinding wheel motor 46 ismounted an amount equal to the wear of the original wheel 235. Thethread ed shaft 66 is accordingly rotated by knob 64 moving the slideblock to relocate the drive spindle 54 off center from the axis ofcradle 44. The rocking of the cradle 44 caused by the corrector cam 24and follower 166 through the rack and pinion 1'76 and 178 will now causethe grinding wheel 236 to move along an arcuate path as prescribed bythe corrector cam 24 for movement .of the cradle 44. The grinding wheel236, though worn, is thus adapted to describe the same path as theunworn wheel 235 insofar as it is disposed at the position of the unwornwheels engagement with the workpiece 18. The corrector cam 24 is adaptedto cause the grinding wheel 236 to describe a path of movement such aswill dispose the wheel in grinding engagement with the workpiece 18 atall times as required to perform the desired tolerance grinding.

In operating the proposed profile or contour grinding machine it isfirst necessary to provide a properly dressed grinding wheel. The wheeldresser 86 is moved into position, the cradle locked by stop 92, thegrinding wheel 20 rotated and the face of the wheel adjusted relative tothe dressing member 90 by movement of the grinding motor 46 on the slideblock 60. The dressing member 90 is then moved across the face of thewheel in a conventional manner. When the dressing operation is completedthe grinding motor 46 is stopped, the stop 92 disengaged from thecradle, and the wheel dresser 86 pivoted to the side of the machine andout of engagement with the grinding wheel.

The maximum work stroke to be taken, that is lengthwise of the workpiece18 and toward its shank, is next set by longitudinal adjustment of thegrinding wheel 20 through movement of slide block 60 upon which thegrinder motor 46 is mounted.

Consideration is next made of the size of the grinding wheel 20 todetermine whether or not the wheel is such as requires that the drivespindle 54 be relocated relative to the axis of rotation of cradle 44.Although the wear after each grinding operation may not be appreciable,the operator should check the size of the wheel after each operation toascertain Whether or not wear correction should be made. This step maybe accomplished in the course of dressing the grinding wheel.

Following the adjustment of the disposition of the drive motor 46 asrequired to properly align the grinding wheel 20 with respect to thecradle axis, the workpiece 18 is next inserted in the chuck 106 andlocked within the jaws 108 with the portion to be ground exasaaaea 7tended outwardly towards the grinding wheel 20. The workpiece 18 is aroughly cast or forged member which is required to be brought withinprescribed tolerances. The general contour of a turbine blade istherefore present and only minimal grinding is required.

Having fluid supplied to all fluid lines preparatory to operation, thatis those which are adapted to carry fluid at the first stages, the pilotvalve 194 is opened to start the fluid motor 114. The workpiece 18 isrotated at a speed prescribed by the setting of the metering valve 192.Neither fluid cylinder 34 or 114 is activated, the fluid passingdirectly through the control valves 206 and 218 and returning to thetank 184. The grinder motor 46 is activated and the grinding wheel 24)rotated at its prescribed speed. The wheel 20 is at this moment spacedapart from the workpiece 18.

The machine operation is initiated by start button 244 which isconnected to control valve 206 diverting fluid flow to the hydrauliccylinder 114 and moving the master cam 22 into engagement with camfollower 120. After a short time delay to eifect such engagement thefluid flow through control valve 218 is diverted to one end of thehydraulic cylinder 34 moving the slide table 14 and consequently thegrinding wheel 20 into grinding engagement with the workpiece 18. As theworkpiece 18 is rotated and moved transversely in conformance with thedictates of the master cam 22 the grinding wheel 2t progresseslengthwise therealong. With compensation being made for wear of thegrinding wheel 20 the cradle 44 will be rocked by the rack and pinion176 and 1178 to enable the worn grinding wheel 20, if such be in use, tofollow the arcuate path which would normally be the peripheral edge of anew grinding wheel.

When the table 14 has moved the grinding wheel 2% along the presetlength of the workpiece 18, the table contacts limit switch 224. Thetable 14 is stopped and dwells in such end position during which timethe fluid flow to hydraulic cylinder 114 is diverted from one end to theother causing the work holder housing 93 to back off the master cam 22from the cam follower 120. When the master cam 22 has been moved out ofengagement with the follower 120 the housing 98 engages limit switch 228which causes fluid to be diverted from one end of the hydraulic cylinder34- to the other for rapidly rea turning the table 14 to its originalposition. The table 14 in returning engages limit switch 232 cutting offthe grinder motor 46. The pilot valve 194 is then shut off and thefinished workpiece 18 removed from the chuck 1%.

The setting of the grinding wheel 20 relative to the axis of cradle 44should be checked prior to inserting another rough workpiece 18 in thework chuck 166 and repeating the operation.

We claim:

1. The method of compensating for work tool wear in a profiling machinehaving the work surface of a Work member adapted to generate an arcuatepath about the rotational axis of a preferred work tool, which methodincludes disposing the working edge of a worn work tool tangentially ofsaid arcuate path, and oscillating said worn tool in an arcuate pathconcentric with said firstmentioned arcuate path and in timed relationwith the movement of said work surface within said arcuate path formaintaining said working edge in continuous working engagement with saidWork member.

2. The method of compensating for grinding wheel wear in a profilegrinding machine having the work surface of a work member adapted togenerate an arcuate path. coincident with the periphery of a grindingwheel of preferred diameter, which method includes displacing the axisof a worm grinding wheel in parallel spaced relation to the axis of saidgrinding wheel of preferred diameter a distance disposing the peripheryof said worn wheel tangentially of the arcuate path of travel of the 75work surface of said work member, and oscillating said worn Wheel aboutthe axis of said grinding wheel of preferred diameter in timed relationwith the movement of said work surface within said arcuate path formaintaining continuous working engagement between said worn wheel andsaid work member.

3. The method of compensating for grinding wheel wear in a profilegrinding machine having a workpiece rotated about a given axis and theirregular external work surface thereof moved in an arcuate pathconcentric with said given axis, which method includes, mounting a worngrinding wheel for rotation about a chosen axis, disposing said chosenaxis in parallel spaced relation to said given axis and the workingperiphery of said worn wheel within the arcuate path traveled by saidworkpiece, oscillating said worn grinding wheel about said fixed axis,and controlling the oscillation of said worn wheel to maintain theworking periphery thereof in engagement with the work surface of saidworkpiece moving in said arcuate path.

4. A profile grinding machine including means for receiving a workmember and translating the surface thereof to be worked along, anarcuate path, means for receiving a work tool and disposing the Workingsurface thereof on said arcuate path, said last-mentioned means beingadjustable relative to said arcuate path and having means operativelyconnected thereto for oscillating the Working surface of said work toolalong said arcuate path for continuous working engagement with said workmember.

5. In a machine adapted to receive a workpiece and to have the surfacethereof to be worked translated along an arcuate path for engagementwith a work tool, means for compensating for work tool wear whichincludes, tool holder means adjustable relative to said arcuate path andadapted to receive a work tool and dispose the working surface thereofon said arcuate path, and means operatively connected to said toolholder means for oscillating the working surface of said tool along anarcuate path coincident with said first-mentioned arcuate path and intimed relation to the movement of said workpiece surface for continuousworking engagement with said workpiece.

6. A profiling machine comprising a work holder for receiving a workmember for rotation, a cradle including a tool holder for receiving awork tool for rotation, means connected to said tool holder for movingsaid tool holder towards said work holder, means connected to said workholder for moving said work holder transversely of the direction oftravel of said tool holder, means operatively connected to said workholder for coordinating the movements of said work member relative tosaid tool holder and moving the work surface thereof in an arcuate pathrelative to the pivotal axis of said cradle, means displacing the axisof rotation of the work tool received by said work holder in parallelspaced relation to the pivotal axis of said cradle for disposing theperipheral edge thereof on the arcuate path traveled by the work surfaceof said work member, and means operatively connected to said cradle forrocking said cradle, the rocking of said cradle translating theperipheral work engaging surface of said work tool in an arcuate pathcoincident with the arcuate path traveled by the work surface of saidwork member.

7. A profiling machine comprising a work holder for receiving androtating a workpiece having an irregular external work surface and fortranslating said workpiece normal to the axis of rotation thereof, arotatable work tool and means for oscillating said rotatable tool in anarcuate path about a reference axis of gyration, means for feeding saidtool towards and away from said workpiece, and cam and drive meansinterconnected with said Work holder and tool oscillating means forrotating and translating said workpiece in timed relation to the oscil-References Cited in the file of this patent 5 UNITED STATES PATENTSMorrison Feb. 26, 1889 Ahearn Nov. 23, 1897 Hanson Apr. 12, 1927 10 10Bryant Mar. 19, 1929 Gannon Ian. 5, 1932 Bryant Aug. 1, 1933 StevensApr. 9, 1935 Bruhl Jan. 21, 1936 Galloway July 22, 1947 Kestell Nov. 7,1950 Seyferth Oct. 27, 1953 Grobey Mar. 9, 1954

